Cutter chain and bit therefor



j Y I, f I

NOV. 6, 1934. T E. PRAY 1,979,344

CUTTER CHAIN AND BIT THEREFOR v Filed March 14. 1952 Patented Nov. 6, 1934 PATENT OFFICE CUTTER CHAIN AND BIT THEREFOR Thomas E. Pray,

Chicago,

Ill., assigner `to- Goodman Manufacturing Company, Chicago, Ill., a corporation of Illinois Application March 14,

Claims.

This invention relates to improvements in cutter chains and bits used in mining machines, and has among other objects to provide a new and novel form of cutter chain bit and block for hold- 5 ing said bit which is of a simplified form and economical construction which will eliminate certian disadvantages in cutter chains as heretofore constructed. f l

Much difficulty and loss of time have hereto- 1O fore been encountered in'm'lning machine cutter chains due to sticking of the bits in the blocks.

This is especially true where the bits are broken 01T in the blocks and no means is provided in the blocks whereby access to the `bits may be obtained without removing thechain from the cutstock of a rectangular cross-section. With `such` bits there is a tendency for the face ofthe bit to bulge out where engaged by the set screw,

especially where a cup-point set screw is used and the bit has been resharpened and used a number of times. There Ais also a tendency during forging lto thicken the-metal or cause it t0 bulge out along the sides of the bit adjacent the cutting point or edge. This causes the bit to cut ineciently andthe bulged portion formed by the set screw tends to tightly engagethe corners of the socket in the cutter chain block and belcome wedged in said socket. Inasmuch as bits are changed frequently during the cutting operation, sometimes as often as once every time a place has been cut by the mining machine where there are impurities in the coal, it isof great advantage to make the extraction of these bits from the block as easy as possible. My invention relates to a block so arranged as to provide ready access to the bit anda bit made from stock which is so shaped as to be more readily formed than formerly, which bit is adapted to cut more eiiiciently, and is of sucha cross-section as to minimize the tendency of said bit to stick within the block.

My invention may be more readily understood with reference to the accompanying drawing whereint i `Figure 1 is a side elevation of a cutter chain block ofthe type embodying my invention with parts broken away and in section to morefclearly show the details thereof and having my improved form of bit supported therein;

Figure 2 is a rear end View of a cutter chain block shown supported in a cutter bar with parts broken away and in section to more clearly show the details of my invention; V

1932, serial No. 598,615

Figure 3 is a transverse sectional view taken through the cutter chain block shown in Figure 1;

`Figures-4:, 5, and 6 are rear end views of other blocks inthe cutter chain supporting the bits in diierent positions than are shown in Figure 1 with parts broken away andin section to more clearly show the details of Ymy invention; and

Figure '7 is a perspective view of the bit embodying my invention.

Like numerals refer to like parts throughout the variousv figures.

Referring now in particular to `the drawings, the device embodying my invention comprises a cutter chain of a usual construction which includes a plurality of blocks indicated by reference characters 10, 11, 11, 12, 12, and 13, 13, respectively, which blocks are adapted to detachably support cutter chain bits indicated by reference character 14, and are connected together by suitablelinks or straps ina usual manner. The cutter chain blocks 10 to 13, inclusive, .are adapted to be guided in suitable guides indicated by reference character 15 formed in a mining machine cutter bar 16 of an ordinary construction in a usual manner which is not herein shown nor described in detail since it is no portion of my invention.

As is customary in cutter chains, one block, herein shown as the block 10, holds the bit 14 in a central position with respect to thel cutter bar; a pair of blocks, herein shown as theblocks 11, 11, hold the bits 14 in a position so their points are spaced upwardly` and downwardly from the center of said cutter bar; and other blocks, herein shown asthe blocks 12, 12 and 13, 13, respectively, hold the bits 14 so` their points are spaced progressively farther from the l#enter of said cutter bar. This holds the bits 14 in` staggered relation with respect to each other and permits the cutter chain to cut a kerf equal in height to the distance between the points of the bits in the blocks 13 which permits the entire cutter bar to be inserted therein along with the cutter chain in a usual manner well known to those skilled in the art. It is apparent that relation of the blocks with respect to each other may be varied to suit varying conditions of cutting.

Each block is provided with a socket 17 which is adapted to receive the bit 14. l The socket 17 is formed with parallel forward and rearward faces having squared corners and sides which extend conVeXly outward from' said socket for `a portion of their length so as to engage parallel sides 18 and faces 19 of the bit`14 and permit said bit to be rmly held therein. The convex sides of the socket 17 provide clearance between the sides of the bit 14 to permit ready withdrawal of said bit in cases where the sides thereof are bulged out or marred. No such clearance, however, is provided between the forward and rearward faces of the bit 14 and the forward and rearward faces of the socket 17, said faces snugly engaging the forward and rearward faces of said socket to prevent movement of said hit within said socket during the cutting operation.

Each cutter chain block is provided with a threaded bore 20 adapted to receive a set screw 21, which set screw is adapted to engage the forward face of the bit 14. As herein shown, the threaded bore 20 extends through the block so said block may be used for cutting in opposite directions by merely changing the position of the bit with respect to said block.

Referring now in particular to one of the novel features of my invention, the body portion of each block is provided with a bored passageway 23 which extends therethrough perpendicular to the sides -of the socket 17 and communicating with said socket. The bored passageway 23 is located beneath the threaded bore 2O and extends through the socket 17 and is so positioned that its center intersects the center line of said socket.

With reference to Figures 2, 4, 5, and 6, it may be seen that the bored passageway 23 in the body portion of each block is so located that it is perpendicular to the sides of the socket 17 and sides 18 of the bit 14 so a center punch may readily be engaged with the sides of said bit for aiding in removing a bit from any of said blocks in cases where they become broken oif and stuck therein (see Figure 2).

Referring now in particular to the bit 14 and several other novel features of my invention, said bit is herein preferably shown as being a pick point bit of the usual type used in cutter chains for cutting coal, although it should be readily apparent that any other type of cutting bit may be used in place of .the pick point bit herein shown. As has hereinbefore been stated, due to the fact that the forward and rearward faces 19 of the bit 14 are engaged in the forward and rearward sides of the socket 17, and due to the vfact that the bit is held in said socket by means of the set screw 21, it may be seen that tightening of said set screw tends to cause the face of the bit 14 engaged thereby to bulge out. 'This causes the edges of the face 19 of the bit 14 engaged by the set screw 21 to bulge and engage and wedge between the corners of the socket 17 which causes said bit to stick in its socket and makes removal thereof difficult or impossible without drilling the bit out and consequently causes loss of time and raises the costs of cutting. While the bored passageways 23 are provided in each block 10 to aid in removal of the bits from their sockets, it is apparent that where the face of the bit has been bulged out by the set screw 21 that the bored passageways 23 in the blocks 10 will not entirely remedy this diiculty.

Due to the speed of the cutter chain and the load on leach bit, it has been found to be impractical to use a set screw other than a cup-point set screw to engage and hold the bit in its block and due to cutting conditions it has been found impractical to form a bit from material of such hardness that it will not bulge when repeatedly engaged by a set screw.

In order to overcome these difficulties and provide a bit which will not stick in the block, I have provided a bit having clearance between the rectangular corners of the socket 17, and in order to provide such clearance the rectangular corners between the sides and faces of said bit are cut away as is indicated by reference character 24 or said bit is formed from material having rounded or beveled edges (see Figure 7). As herein shown, the corners of the bit 14 are chamfered although it may be readily apparent that the corners may be rounded as well as charnfered provided there is sumcient clearance between the edges of the forward face of said bit and the rectangular corners of the socket 17 to prevent fouling of said bit within said socket. It is thus apparent that while engagement of the set screw 21 with the forward face 19 of the bit 14 will tend to swell or bulge the face of said bit, this bulge will be compensated for by the fact that the rectangular corners between the sides and faces of said bit have been removed which will provide clearance between said bit and the corners in said socket and prevent fouling or sticking of said bit within said socket.

The bit 14 is provided with a cutting point 25 which is formed by curving a bar of material forwardly to form a relatively sharp cutting point. The bit 14 is preferably forged from a bar of metal which has the corners between the faces of the sides thereof removed before the forging operation. With this excess of material removed from the corners of the bit, as the bit is curved forwardly to form a relatively sharp cutting point, the tendency of the bit to bulge where curved is minimized and the forging of the bit is simplified thus insuring the provision of a bit which will not bulge where the point has been bent forwardly and minimizing the time required to forge or resharpen said bit.

It may now be seen that I have provided a new and improved cutter chain block and bit therefor so constructed as vto facilitate removal of the bit from the block after the cutting operation when the bit is dull, which bit has been so formed as to eliminate sticking of said bit within said block. It may also be seen that a bit has been provided which may be more readily forged than bits heretofore used which is formed from stock of such a shape as to prevent bulging of the bit during the forging operation.

While I have herein shown and described one form in which my invention may be embodied, it will be understood that the construction and arrangement of the parts may be altered without departing from the spirit and scope thereof. Furthermore, I do not wish to be understood as limiting myself to the specic construction illustrated herein excepting as specifically limited in the appended claims.

I claim as my invention:

1. In a cutter chain for mining machines, a plurality of cutter chain blocks, one of said blocks being a center block and each of said other blocks being inclined upwardly or downwardly from said center block, each of said blocks having a socket therein inclined in a plane parallel to the angle of inclination of said block, said socket being adapted to detachably support a cutter chain bit therein', each of said blocks having a bored passageway therein extending perpendicular to the plane of said socket and intersecting said socket and providing a means of accessibility to said bit whereby said bit may readily be removed from said socket.

2. In a cutter chain for mining machines, a plurality of cutter chain blocks, one of said blocks being a center block, the other of said blocks being inclined upwardly or downwardly with respect to said center block and each of said blocks having a socket thereinv inclined in a plane parallel to the angle of inclination thereof, said sockets having squared corners, parallel forward and rearward faces, and sides which are convex for a portion of their length, a cutter chain bit having chamfered edges adapted to be detachaby carried `by each of said sockets, a set screw adapted to engage the forward face of each of said bits, and a bored passageway in each of said blocks disposed perpendicularly to the sides of said bits and communicating with said sockets and bits, providing a means of accessibility to said bits whereby said bits may readily be removed from f said sockets.

3. In a cutter chain for mining machines, a plurality of cutter chain blocks, one of said blocks being a center block and each of said other blocks being inclined upwardly and downwardly from said center block, each of said blocks having aY socket therein inclined in a plane parallel to the angle of inclination of said block, said socket being adapted to detachably support a cutter chain bit therein, and each of said blocks having a passageway therein extending perpendicular to the plane of said socket and intersecting said socket and providing a means of accesibility to said bit whereby said bit may readily be removed from said socket.

4. In a cutter chain for mining machines, a

plurality of cutter chain blocks, one of said blocks being a center block and each of said other blocks being inclined upwardly and downwardly from said center block, each of said blocks having a socket therein inclined in a plane parallel to the angle of inclination of said block, said socket being adapted to detachably support a cutter chain bit therein and engage the forward and rearward faces and sides of said cutter chain bit and each of said blocks having a passageway therein intersecting and extending perpendicular to the plane of said socket and providing a means of accessibility to said bit whereby said bit may readily be removed from said socket.

5. In a cutter chain for mining machines, a plurality of cutter chain blocks, one of said blocks being a center block, the other of said blocks being inclined upwardly or downwardly with re- 'speet to said center block and each of said blocks having a socket therein inclined in a plane parallel to the angle of inclination thereof, said sockets having squared corners, parallel forward and rearward faces, and sides which are convex for a THOMAS E. PRAY. 

